Communication Device

1. A communication device comprising: a plurality of frame buffers, each configured to store input frames from one or more communication channels; and first and second schedulers configured to cyclically visit the plurality of frame buffers to read a frame from each frame buffer to output to another communication device, wherein the first scheduler reads one frame per visit to each frame buffer at a speed lower than a communication speed of the communication device, and the second scheduler, in parallel with the first scheduler, reads one or more frames per visit to each frame buffer such that read quantity of the second scheduler is defined by a reference value greater than the shortest frame size.

2. The communication device according to claim 1 , further comprising: a cumulative amount monitoring unit configured to store, for each of the plurality of frame buffers, a cumulative read amount defined by a cumulative amount of frames read at least by the first scheduler, the larger the cumulative read amount of a given frame buffer, the smaller the read quantity value of the second scheduler on reading from the frame buffer.

3. The communication device according to claim 2 , wherein, when the cumulative read amount of a given frame buffer exceeds a predetermined value, the second scheduler skips the process of reading a frame from the frame buffer, and when the step of reading a frame from the frame buffer is skipped, the cumulative amount monitoring unit decreases the cumulative read amount of the frame buffer from the previous level.

4. A communication device comprising: a plurality of frame buffers, each configured to store input frames from one or more communication channels; first and second schedulers configured to cyclically visit the plurality of frame buffers to read a frame that should be output from each frame buffer to another communication device; and a third scheduler configured to cyclically visit the plurality of frame buffers to read a frame for external output from each frame buffer, wherein the first scheduler reads one frame per visit to each frame buffer at a speed lower than a communication speed of the communication device, wherein the second scheduler reads one or more frames per visit to each frame buffer such that read quantity is defined by a reference value greater than the shortest frame size, and wherein the third scheduler reads one or more frames such that a restriction on read quantity is defined by another reference value greater than the shortest frame size and smaller than the reference value of the second scheduler.